Screw drivers

ABSTRACT

A Phillips type screw driver bit in which the four radially extending vanes at the bit end of the screw driver shank are provided with wall portions near the apex of the bit that will contact with the adjacent wall surfaces in the cruciform slot in the screw when the bit is inserted into the cruciform slot. The point of novelty lies in providing the wall portions of the vanes with relieved areas that will be spaced from the adjacent wall surfaces in the cruciform slot that lie at the top surface of the screw head. In other words, when the screw driver bit is seated in the cruciform slot in the screw, the relieved portions of the side walls of the vanes will be spaced from the adjacent surfaces of the cruciform slot so that there can be no contact between these opposed surface portions and the upper portion of the cruciform slot (in the screw head) cannot become marred or damaged.

United States Patent [151 3,654,974 [451 Apr. 11,1972

Barnes [54] SCREW DRIVERS [72] Inventor: Bertron Otis Barnes, 6054 Claremont Avenue, Oakland, Calif. 94618 [22] Filed: Apr. 8, 1970 [21] Appl. No.: 26,657

[52] US. Cl. ..145/50 A [51] Int. Cl ...B25b 15/00 [58] Field ofSearch ..145/50 R, 50A

[56] References Cited UNITED STATES PATENTS 2,389,129 11/1945 Bishop ..l45/50 A 2,815,054 12/1957 Cummaro ..l45/50 A 3,234,982 2/1966 Stillwagon ..145/50 A FOREIGN PATENTS 0R APPLICATIONS 427,892 4/1935 Great Britain ..145/50 A Primary Examiner-Andrew R. Juhasz Assistant Examiner-Michael Koczo, Jr. Attorney-William R. Piper [57] ABSTRACT A Phillips type screw driver bit in which the four radially extending vanes at the bit end of the screw driver shank are provided with wall portions near the apex of the bit that will contact with the adjacent wall surfaces in the cruciform slot in the screw when the bit is inserted into the cruciform slot. The point of novelty lies in providing the wall portions of the vanes with relieved areas that will be spaced from the adjacent wall surfaces in the cruciform slot that lie at the top surface of the screw head. In other words, when the screw driver bit is seated in the cruciform slot in the screw, the relieved portions of the side walls of the vanes will be spaced from the adjacent surfaces of the cruciform slot so that there can be no contact between these opposed surface portions and the upper portion of the crucifonn slot (in the screw head) cannot become marred or damaged.

1 Claim, 2 Drawing Figures SCREW DRIVERS SUMMARY OF THE INVENTION An object of my invention is to provide a Phillips screw driver bit in which the four radially extending vanes at the bit end of the screw driver have wall surfaces that will contact with the corresponding wall surfaces near the apex of the cruciform slot in the screw head and in which the wall surface portions of the vanes more removed from the bit end of the screw driver will be relieved so as not to contact the adjacent wall surface portions in the cruciform slot that are disposed near to the top of the screw head. In this way the top of the cruciform slot in the screw cannot be marred by the screw driver nor will the screw driver bit be marred.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a side elevation of a Phillips screw driver shank and bit shown in a larger scale.

FIG. 2 is an end view of the screw driver bit.

DESCRIPTION OF THE PREFERRED EMBODIMENT In carrying out my invention, I illustrate on an enlarged scale, the bit end of my improved Phillips screw driver. The shank 1 has four flutes 2 that are equally spaced around the shank and start at the points 3. These four flutes extend substantially to the apex ll of the bit, see FIG. 1. Each flute 2 has sloping side walls 4 and 5 and a median line 12 lies between the two side walls. The side walls 4 and 5 form vanes 9 that extend from points 6 and 7 down to the apex 1 1 of the bit.

Each vane 9 differs from the usual radial vane in the Phillips screw driver in that the upper side surface portions of the vanes from the points 6 and 7 down to the points 13 and 14 do not have the same slant as from the points 13 and 14 down to the apex 11. The slant of the wall portions from the points 13 and 14 down to the apex 11 is such as to conform to the same slanting surfaces provided in the lower portions of the cruciform slot, not shown, in a Phillips screw, notshown. In other words, the converging side walls of the vanes 9 from the points 13 and 14, and down to the apex 11 of the bit, will contact with the corresponding wall portions near the apex of the cruciform slot in the Phillips screw, not shown.

The important and novel feature of my device is that the upper portions of the side walls of the vanes 9 that lie between the points 6 and 7 of the vanes and down to the points 13 and 14, are relieved; i.e. they are not at the same slant as that of the wall portions between the points 13 and 14 and the apex l1 and indicated by the inclined outer edges 8 of the vane 9. Therefore, the wall portions of the vanes lying between the points 6 and 7 and the points 13 and 14 of the vanes will not contact with the adjacent wall surfaces of the cruciform slot in the Phillips screw, not shown, and the upper edges of the screw slot cannot be marred. The upper portion of each side wall makes an obtuse angle with its associate lower portion of the same side wall. The outer wall 10 of each vane 9 lies in an inclined flat plane extending from the points 6 and 7 and on down to the apex 11. Since I eliminate any damage to the cruciform slot in the screw, the torque between the screw driver and the screw will be increased. Consequently, there will be less throw-out pressure between the cruciform slot walls in the screw and the screw driver.

It will thus be seen that the invention accomplishes the objects to be attained, and it is to be understood that the form of the side walls of the bit of my invention shown in the accompanying drawing is intended by way of exemplification and not by way of limitation and that modifications of the side walls of the bit may be resorted to within the principles of the invention and the scope of the appended claim without departing from the spirit of the invention.

Having thus described the invention what is claimed as new and desired to be secured by Letters Patent is:

l. A screw driver for screws having cruciform recesses in their heads and comprising:

a. a shank having a bit portion formed at one end thereof,

said bit portion including radially extending vanes separated from adjacent vanes by flutes;

b. each vane having its outer wall extending at an incline from the periphery of the shank to the apex of the bit portion;

c. the side walls of each vane having their lower portions converging toward the apex so that these portions will contact the inner adjacent wall portions of the cruciform recess in a screw; and

. the upper portions of the side walls for each vane being inclined at a different angle to that of said lower wall portions so as to make an obtuse angle with the lower wall portion;

. whereby said upper side wall portions will be spaced away from the adjacent upper wall portions of the cruciform recess in the screw when the bit is inserted into the screw recess and therefore the upper side wall portions cannot damage the upper wall portions of the screw recess nor will the bit vanes be damaged. 

1. A screw driver for screws having cruciform recesses in their heads and comprising: a. a shank having a bit portion formed at one end thereof, said bit portion including radially extending vanes separated from adjacent vanes by flutes; b. each vane having its outer wall extending at an incline from the periphery of the shank to the apex of the bit portion; c. the side walls of each vane having their lower portions converging toward the apex so that these portions will contact the inner adjacent wall portions of the cruciform recess in a screw; and d. the upper portions of the side walls for each vane being inclined at a different angle to that of said lower wall portions so as to make an obtuse angle with the lower wall portion; e. whereby said upper side wall portions will be spaced away from the adjacent upper wall portions of the cruciform recess in the screw when the bit is inserted into the screw recess and therefore the upper side wall portions cannot damage the upper wall portions of the screw recess nor will the bit vanes be damaged. 